Emergency lighting, sometimes referred to as egress lighting, is lighting that is activated in the event of power loss. One purpose of emergency lighting is to allow occupants of a building to safely exit the building in the event of a power outage or other emergency. Emergency lighting is mandated for use in commercial buildings by many electrical codes. Such codes generally specify the amount of light that must be provided in the event of power loss and the duration of time for which such light must be provided. For example, U.S. building codes require emergency lighting to provide one footcandle of light for a minimum of 90 minutes along the path of egress during a power outage.
Emergency lighting is commonly provided by emergency light fixtures that are installed with fluorescent luminaires that provide light in non-emergency situations. Solid-state lighting devices may be attractive for replacing these fluorescent luminaires and may offer improved energy efficiency, reduced heat generation, extended life and desired performance characteristics, such as certain color and/or color rendering capabilities. However, the LEDs may require a different emergency lighting module and replacing the existing fluorescent emergency lighting modules would be expensive.